[aquachick]

You know the spill about bettas with other fish, so I won't go there, except to remind you that the new betta may not have the same laid-back personality as your existing one does. I only say that because that is exactly what happened to me. I ended up getting a divider and gave my betta about 2-3 gallons of the tank. I'd go for 3 platies, about 7 danios, 7 neons and either a few mollies (though I think they need a little salt, which some others won't take well) or a group of 5 cory cats. You could use a bottom-level swimmer to balance out. In my opinion, I'd keep the betta you have where he is, maybe use a divider to add another betta and make the centerpiece fish of your new tank a dwarf gourami or something like that. I wouldn't put danios in a 10-gal (done that before too!) bc they are VERY active and the tank just really isn't big enough for them. That's just my oh-so humble opion though. : )

edit: typos